Currently, driving power circuits at high switching frequency is performed in order to downsize and lighten switching power supplies. Along with it, wide band gap semiconductor devices, GaN and SiC, have attracted attention. However, there is a great constrain related to the false turn-on phenomenon produced by gate noise because these wide band gap semiconductor devices have low threshold voltage. If the false turn-on phenomenon occurs, the efficiency of the power supply decreases. Therefore, this paper analyzes the gate noise performance using simulation and experimental tests focusing on the parasitic inductance of the power devices terminals. As a result, it was found that the gate noises can be related to the recovery current of the body diodes. Additionally, this analysis was theorized by the comparison between the experimental results and the theoretical equation using an equivalent circuit.

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This paper discusses a problem that a half-bridge circuit can generate, namely a false trigger by high-speed switching transition. In general, a false trigger occurs by charging a gate-source capacitance because of high-speed voltage transition and influx of current via a reverse transfer capacitance. Therefore, it is thought that the ratio of the input capacitance and the reverse transfer capacitance is important to check whether a false trigger occurs. However, we find another reason and propose a novel assumption. A novel false triggering mechanism appears by considering the source-side parasitic inductance.

This paper analyzes the gate noise performance using simulation and experimental test focused on parasitic inductances of power semiconductor devices' terminals. The gate noise which is over the threshold voltage makes non-active FETs turn on and leads the FETs to a breakdown. Next generation devices which have very high speed switching characteristic are difficult to be dealt with due to the false turn-on problem. The false turn-on mechanism in conventional theory is related to parasitic capacitors and a gate resistor and false turn-on occurs by the current flowing through a reverse transfer capacitor. However, the novel mechanism we proposed is mainly linked to parasitic inductors and recovery current and a non-active FET is switched on due to the oscillation which the energy charged by the current flowing from the source to the gate makes. We verified our theory by experiments, simulations and simplistic circuit equations.